Eosinophilic Leukemia Cell Line Research Articles

Inhibitory effects of azelastine hydrochloride on Ca2+influx, actin polymerization and release of eosinophil cationic protein of an eosinophilic leukaemia cell line EoL-1

The inhibitory effects of azelastine hydrochloride on PAF-induced and fMLP-induced Ca2+ influx, actin polymerization and calcium ionophore A23187-induced and aggregated IgG-induced release of eosinophil cationic protein (ECP) of an eosinophilic leukaemia cell line, EoL-1, were examined. EoL-1 cells cultured with 0.2 mM dibutyryladenosine-cyclic monophosphate for 48 hours showed an increase in intracellular free Ca2+ concentration ([Ca2+]i) and actin polymerization when stimulated by PAF and fMLP. Azelastine hydrochloride inhibited PAF-induced and fMLP-induced Ca2+ influx ([Ca2+]i) in a dose-dependent manner with an IC50 of 1 x 10(-8) M and 1 x 10(-7) M, respectively. It also inhibited PAF-induced and fMLP-induced actin polymerization in a dose-dependent manner up to 40% and 30%, respectively. EoL-1 cells were differentiated to contain ECP in their eosinophilic granules when cultured for 9 days with supernatants of a human adult T cell leukaemia cell line, HIL-3 (HIL-3 sup). Calcium ionophore A23187 and aggregated IgG induced the secretion of ECP by EoL-1 cells. Azelastine hydrochloride inhibited the secretion of ECP in a dose-dependent manner. These inhibitory effects were seen even at therapeutic concentrations of 10(-8) M to 10(-9) M. These results indicate that the therapeutic effects of azelastine hydrochloride as an anti-allergic agent may include inhibition of the accumulation of eosinophils into the locus of allergic inflammation and of the release of cytotoxic granules from eosinophils.

Effects of recombinant tumour necrosis factor on antibody-dependent eosinophil-mediated damage to Schistosoma japonicum larvae.

Human recombinant tumour necrosis factor (rTNF) enhanced monoclonal IgE-dependent eosinophil-mediated cytotoxicity to schistosomula of Schistosoma japonicum in a dose-dependent manner. The enhancing effect of rTNF was also observed for the antibody-dependent cytotoxicity of a human eosinophilic leukemia cell line, EoL-3, but not of another cell line, EoL-1. Observation by a slow-motion movie camera demonstrated that activated EoL-3 cells adhered to the surface of schistosomula by 6 h after incubation, which triggered intracellular movement of eosinophil granules. The granules were concentrated toward the surface of the larvae and then degranulation started. The cell membrane was left as a balloon-like remnant. Cell sorting analysis by FACStar indicated that the expression of receptors for C3bi (CR3) and low affinity FcR for IgE (Fc epsilon RII) increased on the surface of EoL-3 cells after stimulation with rTNF, while this was not observed for EoL-1 cells.

Regulation of the expression of leukocyte function-associated antigen-1 (LFA-1) and intercellular adhesion molecule-1 (ICAM-1) on a human eosinophilic leukemia cell line EoL-3

The effects of several cytokines and phorbol myristate acetate (PMA) on LFA-1 and ICAM-1 expression on a human eosinophilic leukemia cell line. EoL-3, were investigated and compared with those of a human monocytic leukemia cell line, U937. EoL-3 cells expressed large amounts of LFA-1 and small amounts of ICAM-1, and their expression was regulated similarly in EoL-3 cells and U937 cells. Interferon-γ (IFN-γ) enhanced ICAM-1 expression but not LFA-1 expression, and PMA augmented both LFA-1 and ICAM-1 expression. IFN-γ and PMA showed an additive effect on ICAM-1 expression. These results collectively suggest that expression of LFA-1 and ICAM-1 is regulated differently and that IFN-γ and PMA regulate the expression through different mechanisms. PMA but not IFN-γ induced homotypic adhesion of EoL-3 and U937 cells, suggesting that PMA but not IFN-γ activated the adhesive function of these cells. Staurosporin, an inhibitor of protein kinases (PKs), partly suppressed IFN-γ- and PMA-augmented expression of ICAM-1 on EoL-3 and U937 cells, but did not affect PMA-augmented LFA-1 expression, suggesting that staurosporin-sensitive PKs are involved in IFN-γ- and PMA-augmented ICAM-1 expression but not in PMA-augmented LFA-1 expression. The role of protein kinase C (PK-C) in these mechanisms was not revealed because a PK-C inhibitor, H-7, did not show any definitive effect on IFN-γ-and PMA-induced expression of LFA-1 and ICAM-1. Moreover, cyclic AMP (cAMP)- and cGMP-dependent pathways were not shown to be involved in the augmentation of the expression of these molecules.

EoL-1, a human eosinophilic cell line.

EoL-1 cells, a recently established human eosinophilic leukemia cell line, have cytological features of myeloblasts under normal culture conditions, and differentiate not only phenotypically but also functionally into eosinophils by a number of stimuli. EoL-1 cells are particularly useful for analyzing leukemic cell differentiation and the properties of malignant eosinophils. EoL-1 cells are also a useful in vitro model for studying human eosinophil functions and their regulation.

Differentiation of a human eosinophilic leukemia cell line (EoL-1) by a human T-cell leukemia cell line (HIL-3)-derived factor

Differentiation of a human eosinophilic leukemia cell line, EoL-1, induced by the culture supernatant of a human ATL cell line, HIL-3 (HIL- 3 sup) was compared with differentiation induced by defined cytokines. HIL-3 sup induced EoL-1 cells to express eosinophilic granules and segmented nuclei after 6 to 9 days of incubation. HIL-3 sup also induced the expression of Fc epsilon receptor II (Fc epsilon RII/CD23) and an eosinophil differentiation antigen EO-1 mainly on eosinophilic granule (+) cells. Furthermore, HIL-3 sup induced EoL-1 cells to respond to an eosinophil chemotactic factor, platelet activating factor. HIL-3 cells express messenger RNA (mRNA) of interleukin-5 (IL- 5), macrophage colony-stimulating factor (M-CSF), and IL-3 but not granulocyte CSF (G-CSF). Granulocyte-macrophage CSF (GM-CSF) and tumor necrosis factor-alpha (TNF-alpha) were detected in the HIL-3 sup. Recombinant IL-2 (rIL-2), rIL-3, rIL-4, rIL-5, rM-CSF, and rGM-CSF did not induce eosinophilic granules. rG-CSF induced a few eosinophilic granule (+) cells, and TNF-alpha, which did not induce eosinophilic granules by itself, enhanced the ability of G-CSF to induce them. However, G-CSF and TNF-alpha did not induce the expression of Fc epsilon RII and EO-1 antigen. Moreover, anti-G-CSF, anti-TNF-alpha, anti-GM-CSF, anti-IL-3, and anti-IL-5 antibodies did not suppress the effect of HIL-3 sup on the differentiation of EoL-1 cells. All the data suggest that HIL-3 sup contains an unidentified factor that induces differentiation of EoL-1 cells, and that EoL-1 cells and HIL-3 sup provide an important model for the examination of differentiation mechanisms and functions of eosinophils.

Differentiation of a Human Eosinophilic Leukemia Cell Line (EoL-1) by a Human T-Cell Leukemia Cell Line (HIL-3)-Derived Factor

AbstractDifferentiation of a human eosinophilic leukemia cell line, EoL-1, induced by the culture supernatant of a human ATL cell line, HIL-3 (HIL-3 sup) was compared with differentiation induced by defined cytokines. HIL-3 sup induced EoL-1 cells to express eosinophilic granules and segmented nuclei after 6 to 9 days of incubation. HIL-3 sup also induced the expression of Fce receptor II (Fce RM/CD23) and an eosinophil differentiation antigen EO-1 mainly on eosinophilic granule (+) cells. Furthermore, HIL-3 sup induced EoL-1 cells to respond to an eosinophil chemotactic factor, platelet activating factor. HIL-3 cells express messenger RNA (mRNA) of interleukin-5 (IL-5), macrophage colony-stimulating factor (M-CSF), and IL-3 but not granulocyte CSF (G-CSF). Granulocyte-macrophage CSF (GM-CSF) and tumor necrosis factor-α (TNF-α) were detected in the HIL-3 sup. Recombinant IL-2 (rlL-2), rlL-3, rlL-4, rlL-5, rM-CSF, and rGM-CSF did not induce eosinophilic granules. rG-CSF induced a few eosinophilic granule (+) cells, and TNF-α, which did not induce eosinophilic granules by itself, enhanced the ability of G-CSF to induce them. However, G-CSF and TNF-α did not induce the expression of FceRII and EO-1 antigen. Moreover, anti-G-CSF, anti-TNF-α, anti-GM-CSF, anti-IL-3, and anti-IL-5 antibodies did not suppress the effect of HIL-3 sup on the differentiation of EoL-1 cells. All the data suggest that HIL-3 sup contains an unidentified factor that induces differentiation of EoL-1 cells, and that EoL-1 cells and HIL-3 sup provide an important model for the examination of differentiation mechanisms and functions of eosinophils.

Regulation of Fcγ receptor subtype expression on a human eosinophilic leukemia cell line EoL-3: Participation of cAMP and protein kinase C in the effects of interferon-γ and phorbol ester

We investigated the effects of interferon-γ (IFN-γ), phorbol myristate acetate (PMA), and dibutyryl cAMP (Bt 2cAMP) on FcγR subtype expression on a human eosinophilic leukemia cell line, EoL-3. Unstimulated EoL-3 cells expressed FcγRII as determined by monoclonal antibody (mAb) IV-3, whereas there was little or no FcγRI and FcγRIII expression as determined by mAbs 32.2 and 3G8, respectively. IFN-γ induced FcγRI expression, and Bt 2 cAMP, which did not induce FcγRI expression by itself, showed an additive effect on IFN-γ-induced FcγRI expression. FcγRII expression was augmented by IFN-γ, PMA, and Bt 2 cAMP. Bt 2 cAMP also showed an additive effect on IFN-γ-augmented FcγRII expression. FcγRIII expression could be induced only by IFN-γ plus Bt 2 cAMP. H-7, a protein kinase C (PK-C) inhibitor, suppressed the enhancement of FcγR subtype expression induced by these reagents. These results show that FCγR subtype expression on EoL-3 cells is regulated differently in each subtype and that cAMP and PK-C play important roles in the regulation.

Ketotifen inhibits PAF-induced actin polymerization in a human eosinophilic leukaemia cell line, EoL-1

The inhibitory effect of ketotifen on platelet activating factor (PAF)-induced actin polymerization in a human eosinophilic leukaemia cell line, EoL-1, was examined by flow cytometry with the use of reagents specific for the filamentous form of actin (F-actin). Actin polymerization has been considered to be essential for locomotion of cells, chemotaxis and chemokinesis, and thus it reflects the chemotactic reaction of EoL-1 cells stimulated by PAF. Unstimulated EoL-1 cells showed little PAF-induced actin polymerization, whereas EoL-1 cells cultured for 9 days with the supernatant of a human ATL cell line, HIL-3 (HIL-3 sup), showed marked actin polymerization when stimulated with PAF. The actin polymerization in EoL-1 cells induced by PAF was seen in a dose-dependent manner at concentrations of 10(-10) M to 10(-6) M of PAF, and the maximum effect was seen at 10(-7) M of PAF. CV-3988, a specific antagonist of PAF, inhibited 80% of the actin polymerization in EoL-1 cells induced by PAF at a concentration of 10(-5) M. Ketotifen inhibited up to 40% of the PAF-induced actin polymerization of EoL-1 cells in a dose-dependent manner at concentrations of 10(-9) M to 10(-5) M. These results suggest that ketotifen may play an important role in the prevention of eosinophil-induced inflammation in allergic disorders by inhibiting PAF-induced chemotaxis of eosinophils.

Transforming growth factor β and dexamethasone suppress the expression of Fcϵ receptor 2 (CD23) on a human eosinophilic cell line EoL-3

The effects of interferon-alpha (IFN-alpha), INF-gamma, transforming growth factor beta (TGF-beta) and dexamethasone on low-affinity Fc receptors for IgE (Fc epsilon R2/CD23) expression on a human eosinophilic leukemia cell line, Eol-3, were examined. Fc epsilon R2/CD23 expression was enhanced by both IFN-alpha and IFN-gamma, and suppressed by TGF-beta and dexamethasone. Northern blot analysis revealed that these reagents regulate the Fc epsilon R2/CD23 expression from mRNA level: both IFN-alpha and IFN-gamma increased the amount of Fc epsilon R2/CD23 mRNA, while both dexamethasone and TGF-beta decreased Fc epsilon R2/CD23 mRNA, where the effect of dexamethasone was much stronger than that of TGF-beta. In comparison with IFN-alpha, IFN-gamma seemed to enhance preferentially the release of surface Fc epsilon R2/CD23, which resulted in the increase of soluble Fc epsilon R2/CD23. These results suggest that these reagents may play important regulatory roles in allergy and in helminth infections via their effects on Fc epsilon R2/CD23 expression on eosinophils.

Differential regulation of the low affinity Fc receptor for IgE (Fc epsilon R2/CD23) and the IL-2 receptor (Tac/p55) on eosinophilic leukemia cell line (EoL-1 and EoL-3).

Two types of activation Ag, low affinity FcR for IgE (Fc epsilon R2)/CD23 and IL-2R (Tac/p55), were expressed and differently regulated on human eosinophilic leukemia cell lines (EoL-1 and EoL-3). Because the binding of IgE on EoL-3 cells was completely inhibited by H107 (anti-Fc epsilon R2/CD23 mAb) but not by irrelevant mAb, essentially all the low affinity Fc epsilon R2 on EoL-3 seemed to be the Fc epsilon R2/CD23 molecules. Both IL-4 and IFN-gamma enhanced the surface expression of Fc epsilon R2, whereas IL-1, IL-2, and IL-5 showed no effects, as determined by surface staining with anti-Fc epsilon R2 antibody (H107). In contrast to Fc epsilon R2 up-regulation, IL-4 and IFN-gamma showed a differential effect on the regulation of IL-2R (Tac/p55). Whereas IFN-gamma up-regulated the receptor expression of IL-2R/Tac, IL-4 did not. The result suggests that these lymphokines are involved in the different aspects of the activation pathway of the eosinophils. The possible role of Fc epsilon R2 and IL-2R on the function of eosinophils in allergic reaction is discussed.

Establishment and Characterization of a New Human Eosinophilic Leukemia Cell Line

A human eosinophilic leukemia cell line, designated as EoL, was established from the peripheral blood of a patient with Philadelphia chromosome-negative eosinophilic leukemia (EL). The EoL cell line grows in single cell suspension with a doubling time of 48 hours for about one year. The reactivity of these cells was tested with a panel of monoclonal antibodies; they were found to express surface IA antigen, myeloid antigen (IF10, MY9) and membrane receptors for interleukin 2 (IL-2, Tac antigen). Under standard culture conditions, a small percentage of cells having more typical eosinophilic characteristics was present. These cells had cytoplasmic granules and were positive for Luxol-fast-blue and eosinophil peroxidase. Under culture conditions to induce the maturation of myeloid cells, such as alkaline medium or addition of dimethyl sulfoxide (DMSO), the frequency of cells with typical eosinophilic features increased to about 40%. In addition, cytogenetic studies showed that cultured cells and original leukemic blasts presented similar chromosome abnormalities. EoL seems to be a unique leukemic line committed to the eosinophilic lineage and can provide a useful in vitro model for the study of malignant eosinophilic properties.

Establishment and characterization of a new human eosinophilic leukemia cell line

A human eosinophilic leukemia cell line, designated as EoL, was established from the peripheral blood of a patient with Philadelphia chromosome-negative eosinophilic leukemia (EL). The EoL cell line grows in single cell suspension with a doubling time of 48 hours for about one year. The reactivity of these cells was tested with a panel of monoclonal antibodies; they were found to express surface IA antigen, myeloid antigen (IF10, MY9) and membrane receptors for interleukin 2 (IL-2, Tac antigen). Under standard culture conditions, a small percentage of cells having more typical eosinophilic characteristics was present. These cells had cytoplasmic granules and were positive for Luxol-fast-blue and eosinophil peroxidase. Under culture conditions to induce the maturation of myeloid cells, such as alkaline medium or addition of dimethyl sulfoxide (DMSO), the frequency of cells with typical eosinophilic features increased to about 40%. In addition, cytogenetic studies showed that cultured cells and original leukemic blasts presented similar chromosome abnormalities. EoL seems to be a unique leukemic line committed to the eosinophilic lineage and can provide a useful in vitro model for the study of malignant eosinophilic properties.